iPhone email braintwister - “one of the recipient addresses is invalid”
A real client headache. The email address I knew was fine and email sending was broken in general. I eventually found directions to manually add user and password in the “optional” send mail server fields - even if you have SSL enabled.
Enter your Username and Password for your OUTGOING MAIL SERVER [Apple Support Discussion of the topic]
This is the step that fixed the issue both times when I ran into them.
Go into Settings > Mail, Contacts and Calendar > Your Account > Tap the Outgoing (or SMTP) Server > Tap Primary Server > Enter Your Username and Password in the Optional fields.
Username is usually the first part of your email address (everything before the @) or it can also be your entire email address. Password is the one you’d use to log into its webmail.
Usually, these “optional” fields are truly optional. In this case, having them filled in fixed the issue.
